Safety test for Gaganyaan

Onsaturday, Isrowilltesttheperformanceof thecrewescapesystemof India’splannedhumanspace flightmission. Crewsafetyistoppriorityforthemission, andthisisthe firstof aseriesof testsbeforeisro attemptstoliftahumantospace. Thespaceagencywillalsodemonstrateitsne

ON SATURDAY, less than two months after thechandrayaan-3moonlanding, Isrowill carry out the first of a series of tests of systems and procedures with the aim to ultimatelylaunchanindianastronautintospace, perhaps in 2025.

The Flight Test Vehicle Abort Mission-1 (TV-D1) will demonstrate the performance ofthecrewescapesystemofthegaganyaan project. Theflightwillbethefirstoftwoabort missions totest the safety mechanisms that will allow the Gaganyaan crew to leave the spacecraft in an emergency.

The test exercise will see the rocket rise toanaltitudeofalmost17kmbeforeanabort signal is triggered, leading to the separation of thecrewmodule, whichwilldescendusing a parachute for a splashdown in the Bay of Bengal.

The test mission will last a total 532 secondsfromliftoffat8amtothecrewmodule splashdown about 10 km from the Sriharikota coast. The rocket, ISRO’S new, low-costtestvehicle, willreachapeakrelative velocity of 363 metres/ second (about 1307 km/ hr) during the flight. The Crew Module will be empty for the test.

What will be tested?

Saturday’stv-d1flightwilldemonstrate, first, the new Test Vehicle — this is the reason why the test has been named Test Vehicle-demonstration 1 (TV-D1).

Second, it will demonstrate a basic version of the Crew Module — the capsule in which the astronauts will be seated during the Gaganyaan human space flight. The test willcheckthefunctioningofsystemsforseparating the Crew Module from the rocket in case of a mid-flight emergency (abort mission) and the escape of astronauts.

ISRO’S technical definition of the TV-D1 missionis,“in-flightabortdemonstrationof Crew Escape System (CES)”. The flight will “simulatetheabortconditionduringtheascent trajectory corresponding to a Mach numberof1.2encounteredinthegaganyaan mission”, includingcrewmoduleseparation and its safe recovery.

The new Test Vehicle

While the full-fledged test flight of the Crewmoduleintospaceandbackwillbecarriedoutonthehumanratedlvm3rocket(an upgraded version of the heavy lift GSLV Mk III rocket) in 2024, for the TV-D1 mission, ISRO will use a low-cost basic rocket that it has built specifically to test systems.

This Test Vehicle will use existing liquid propulsion technology, but has innovations suchasthethrottleableandrestartablel110 Vikas engine (which forms the core second stageofthelvm3rocket), whichiscapableof controlling propellant use.

The only previous test flight of the Crew Module — called the Crew Module Atmospheric Re-entry Experiment or CARE — on December 18, 2014, used a GSLV Mk III rocket. But since each GSLV Mk III launch costs Rs 300-400 crore, ISRO has developed thecheapertestvehicle. Thegaganyaanhumanspaceflightprogrammehasabudgetof around Rs 9,000 crore.

“We will have many tests flights of the human capsule using a developmental launchvehiclecalledthetestvehicle...,” ISRO chairman Dr S Somanath had said in 2018, whenhewasdirectorofthevikramsarabhai Spacecentre, whichhasdevelopedthenew rocket. “It (the Crew Escape System of the Gaganyaanmission) isthekey, andweneed to test it a number of times without incurring large costs.”

ISRO will use the Test Vehicle for several concepts that are under development, including the Scramjet engine technology for re-usable space launch vehicles.

Crew Escape System

On October 11, 2018, a failure of the Russian Soyuz FG rocket led to a premature end of Expedition 57 to the International Spacestation(iss). Assoonasthefailurewas detected at an altitude of 50 km, the Crew Modulewasseparatedfromtherocketinan emergency operation, and the two astronauts aboard the mission, Alexey Ovchinin of Roscosmos and Nick Hague of NASA, landedonearth402kmfromthelaunchsite atbaikonurcosmodromeinkazakhstan. The failure of the Soyuz MS 10 mission was the firstmid-flightfailureofasoyuzrocketsince 1975, and the first failure of the Soyuz FG rocket in 55 launches.

Isrohasputsafetyofthecrewatthecentre of the Gaganyaan project, and has persuadedtheuniongovernmentthatthe2022 deadlinesetbytheprimeministeronaugust 15,2018shouldberelaxedinordertoensure a safe and successful mission.

The Crew Module must be safe for astronautsunderconditionsofveryhighheatand pressure, and must have a reliable escape mechanism in the event of an emergency. Isroisdevelopingenvironmentalcontroland lifesupportsystemsforthecrewmodule, as wellasanintegratedvehiclehealthmanagementsystemwhichcansenseanomaliesthat could put the life of an astronaut at risk, and trigger actionsto abort the mission.

Some of these systems will be tested in thetv-d1flight. The2014caretesthadassessedtechnologiesincluding“theperformance of parachute-based deceleration system, and a “Pad Abort Test — PAT” was conducted in July 2018.

Stages of TV-D1 mission

After a flight of about a minute, at an altitude of 11.7 km, the Crew Escape System will separate from the Test Vehicle; and after about 90 seconds, the Crew Module will separate from the escape system. It will deploy parachutes, and descend slowly to the surface over about seven minutes. A diving teamandshipoftheindiannavywillrecover the Crew Module from the Bay of Bengal.

“This Test Vehicle mission with this CM (Crew Module) is a significant milestone for theoverallgaganyaanprogrammeasanearcompletesystemisintegratedforaflighttest. Thesuccessofthistestflightwillsetthestage fortheremainingqualificationtestsandunmanned missions, leading to the first Gaganyaanmissionwithindianastronauts,”

ISRO has said.

Status of preparations

Graphic:isro

Drsomanathhassaidthatthetimeframe for the Gaganyaan mission is now 2024 and even beyond, if failures are experienced in the development stages. “...We do not want to rush... The primary objective of human space flight is a sure-shot, safe mission. We have redefined it in such a way that we will achievesuccessintheveryfirstattempt,” he said earlier this year.

“The current schedule is that there will be an unmanned mission in the beginning of nextyear. Thisyearwewillhavetheabort missions. The manned mission is being talked about for the end of 2024 or early 2025. Itdependsonvariousotherscenarios,” the chairman said.

ISRO has completed the human rating of the LVM 3 rocket which will be used for the Gaganyaanmission. Onmay13,2022, itcompleted the static test of a human-rated solid rocketbooster(hs200) thatwillbeusedinthe firststageof therocket. Thetestingof thehuman-rated versions of the liquid propellant L110-gengineforthesecondstageofpropulsion and the third stage C25-G engines with cryogenicpropellanthasalsobeencompleted.

Fourastronautsfromtheindianairforce selected for the mission have undergone traininginrussia. Theywillundergofurther training ahead of the final mission.